Grate



June 20, 1933- o. T. soLBERG ET AL GRATE 3 Sheets-Sheet Filed Sept. 3, 1930 SW1/Wou l y T150 Zef 'MSRO ZZ HMM/l June 20, 1933. o. T. SOLBERG ET AL GRATE 3 Sheets-Sheet 2 0, T30 Z ZW El' Filed Sept. 3, 1930 .gulle 2G, 1933. Q T, SOLEERG m AL ,914,873

GRATE Filed Sept. 5, 1950 3 Sheets-Sheet 3 amante@ ASLZQ!" 9 www5, HMM/ggf narra.

OSCAR T. SOLBERG, OF KLEENB'URN,

OFFECE CHRSTIAN Il. SHOTT, OF MONARCH, AND

HARRISON M. WALKER, OF KLEENBRN, "WYOMNG, ASSIGNORS TO KLEENBURN STOKER CORlORATION, F KLEENBRN, W'YOMING, A CORPORATION OF WYOMING GRATE Application iled September 3, 1930.

rlhis invention relates to improvements in fuel feeding and burning mechanism designed primarily for consuming fuel in small or screenings sizes.

The primary object of the present invention is to provide a rotary grate in association with an air blast, upon which the fine fuel is discharged from a feeding mechanism as the grate slowly revolves, the rotation of the grate and the feeding of the fuel thereto being so proportionately timed that all of the fuel discharged onto the grate will be completely consumed before it makes one revolution with the grate so that the ash remaining may be removed to prepare the grate for additional fresh fuel.

Another object of the invention is to provide an improved rotary grate for burning fine fuel by means of an air current forced upwardly therethrough, in which bars of novel design are employed, the design of the bars being such that air may be forced freely upwardly through the grate but fuel and ashes will be prevented from passing downwardly therethrough.

A still further object of the invention is to provide a rotary grate structure designed to have an air current forced upwardly therethrough, with which is associated means fo-r progressively decreasing the amount of air passing therethrough from the point where fresh fuel is discharged onto the grate around to a point just preceding the fresh fuel receiving point or area 'so I that the greatest amount of airwill be forced upwardly through the fresh fuel charge and practically no air will be passed through the grate at the point where the charge is entirely consumed and only ash remains.

Other objects of the present invention are to provide a novel means for supporting and rotating a grate structure of the character embodying the present invention, novel means for feeding fine fuel to the rotating grate; novel means for removing ash from the grate during the rotation thereof; and novel means for mounting the grate within a furnace fire box whereby the fuel on the grate is prevented from working down bo- Seial No. 479,546.

tween the rotating grate structure and the adjacent fire boX wall.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, with the understanding, however, that the invention is not confined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes or modiications mark no material departure from the salient features of the invention as eX- pressed in the appended claims.

In the drawings Figure l is a view in side elevation of the device embodying the present invention showing the same in working position.

Figure 2 is a vertical sectional view thr ugh the grate structure and adjacent portions of a furnace.

Figure 3 is a view in top plan of a portion of the grate unit and the fuel feed pipe.

Figure Ll is a sectional view taken upon the line 4 4 of Figure 2.

Figure 5 is a detailed elevational view of the conveyor screw casing showing the discharge opening therefor.

Figure 6 is a transverse sectional view of the conveyor casing and screw taken on the line 6 6 of Figure 3.

Figure 7 is a developed view of the apertured terminal portion of the air conducting pipe for the unit.

Referring more particularly to the drawings wherein like numerals of reference indicate corresponding parts throughout the several views, the numeral 1 indicates generally the base of the fuel burner structure embodying the present invention, which base, together with the grate structure carried thereby, is designed for installation in the ash pit of the furnace structure in which the grate is to be installed, a portion of the furnace ash pit or chamber wall being indicated by the numeral 2 while a portion'of the wall of the fire boX is indicated by the numeral 3.

The base structure l which supports the grate and other elements of the mechanism is here shown as being of pyramidal design and in the form of a casing, the apex of which has been cut off and replaced by the fiat centrally apertured top plate 4. It is, of course, to be understood that the base here shown is only one of a number of designs which may be employed without in any way affecting the efficiency of the grate or departing from the spirit of the invention.

The base 1 has extended thereinto an air tube 5 which turns upwardly at its inner end to pass through the passage 6 through the plate 4 terminating in the vertically disposed portion 7 the upper end of which is closed as indicated at 8 while the wall thereof is provided with a series of circumferential apertures 9 which are of gradually decreasing size from one end of the series to the other. The air tube 5 may lead into the furnace ash pit 2 through the usual door thereof, it being connected at its outer end to a blower 10 which is connected with and operated by a motor 11 or other suitable mechanism. The connection between the motor and the blower has interposed therein a suitable gear mechanism 12 for 'transmitting power at a reduced speed through a shaft 13 which leads therefrom into the ash pit, the inner end of thisshaft being supported in a suitable bearing 14 adjacent the upturned portion 7 of the air tube. The use to which this shaft is put will become ap )arent as the description proceeds.

ounted to rotate about the upturned end portion 7 of the air tube, upon the plate 4 is the grate unit which is indicated generally by the numeral 15. This unit comprises a flat circular chamber 16 in the center of the bottom of which an opening 17 is formed from which there extends downwardly a sleeve 18 which receives the portion 7 of the air tube and which rests at its lower end upon the plate 4 in the manner shown. The interior of this circular chamber 16 is divided into a plurality of compartments 19 by the radially disposed walls 2O which extend from the outer wall of the chamber inwardly to the edge of the opening 17. As shown the inner ends of these walls 2() come into close proximity to the apertured upturned end 7 of the air tube and the apertures 9 are so spaced that when one thereof is in complete registration with an opening between a pair of the walls 20, each of the others will also be in complete registration with an opening between a pair of adjacent walls so that air will be delivered through each opening 9 into an adjacent compartment 19. Since the apertured upturned end of the air tube is stationary and the grate unit 15 rotates thereabout, it will be seen that each of the compartments 19 will pass from one aperture to the other and as the apertures gradually decrease in size from the largest thereof each compartment will receive a smaller amount of air as it rotates about the pipe end 7.

The walls 2O serve to support at the top of the chamber 16 a plurality of annular grate bars, each of which is indicated gcnerally by the numeral 21.

As shown, each of these grate bars 21, with the exception of the inner and outer ones 21'a and E21b respectively, comprises a central portion 22 disposed at an inclination with respect to the vertical, along the upper edge of which is formed a downwardly and inwardly inclined flange portion 23 while along the lower edge there is formed an upwardly and outwardly inclined flange portion 24, the lower edge of the portion 22 where it oins the flange portion 24 resting in suitable recesses 25 formed in the top edges of the walls 20. Each of the grate bars thus forms a hip and a valley, the flange on one side of the hip of each bar being extended into the valley of an adjacent bar but held in spaced relation to the parallel portion thereof to provide an air passage 26. It will be seen that the disposition of the air passages 26 between the bars is such that when the air comes up from beneath the grate it must first flow down into the valley portion of each bar and then change its course and How upwardly again so that fuel and cinders upon the grate will be prevented from working through the air passages between the bars and falling into the compartments 19 therebeneath.

The outer bar 211 of the grate is formed to provide a ring 27 which rests in a suitable recess formed in the inner side of the vertical wall of the chamber 16 and is provided with an inwardly and downwardly extending flange portion 2S which extends into the valley of the adjacent grate bar 21, while the inner bar 21a is also in the form of a ring, here indicated by the numeral 29, from which there extends outwardly and downwardly the web terminating in the upturned flange 3l to form a valley for the reception of the downturned flange 23 of the adjacent grate bar.

The ring 29 of the inner grate element 21a surrounds a head piece or cap 32 which is mounted upon the top edges of the walls 20 over the end of the air tube portion 7. This head piece is provided with a central upstanding stub or bearing post 33.

Then installing the present grate structure in a furnace, there is provided as a sealing medium between the lower edge of the fire box wall 3 and the outer portion of the grate unit at the top thereof, a sealing ring 34 which, adjacent its inner edge. overlies the top edge of the outer wall of the circular chamber 16 and the outer grate bar or ring 21h, having a downturned lip 'gli or flange 35 which overlies the `inwardly and downwardly extending portion 28 of the ring in the manner shown. This sealing ring 34 bears firmly against the lower edge of the fire box wall and thus acts to prevent fuel working off of the grate over the side thereof and also acts to prevent the passage of air up around the outside of the grate unit and into the re box without passing through the grate.

Extending into the fire box from the exterior of the furnace is a fuel feed pipe 36, the inner end of which is closed as indicated at 37 and hassecured thereto a bearing ring 38 which surrounds the bearing post 33. The outer end of this fuel feed pipe 36 may be supported in any suitable manner as, for example, upon the supporting legs 39 and has communication with the lower end of a fuel hopper 40. Extending through the fuel feed pipe 36 is a shaft 41 carrying a conveyor screw 42, the outer end of this screw having chain and sprocket connection with the shaft 13 as indicated at 43.

At its inner end the fuel supply pipe 36 has formed therethrough a fuel discharge opening 44 which is slightly tapered, being of greatest width adjacent the inner end of the pipe. This opening is so positioned as to discharge fuel onto the grate in the direction in which the grate is rotating, and because of the peculiar formation of the discharge opening the screw works the |fuel all the way to the larger end of the opening so that it will be evenly distributed on the grate instead of being dumped in a large quantity near the outer side of the grate.

Upon the opposite side of the fuel supply pipe 36 from the Vfuel discharge opening 44 there is secured the arcuate ash scraper 45, the lower edge of which comes into close proximity to the tops of the grate bars 21.

The bottom of the circular chamber 16 has secured thereto about the periphery the ring gear 46 with which is connected a pinion gear 47 carried upon the shaft 13.

From the foregoing description it will be readily seen that when the present fuel burner structure is set into operation thel motor, being directly connected with the blower 10 will cause the blower to operate rapidly to supply a blast of air to the compartments 19 of the grate unit. Through the medium of the reduction gearing in the housing 12 the shaft 13 and consequently the grate unit and fuel feeding screw 42, are turned at a slower speed. As the screw 42 rotates it will conduct the fine fuel .from the hopper 40 to the discharge opening 44 where it will be discharged onto the grate bars 21. The rotation of the grate unit is so timed with the rate of combustion of the fuel that as the fuel reaches the opposite side of the pipe 36 it will be entirely consumed and the ash remaining will be swept from the surface of the grate by the scraper' 45. It will be noted that the sealing ring 34 adjacent the scraper 45 has been cut away so that the ashes removed from the grate may fall into the ash pit beneath the fire box or into a suitable chute by means of which they may be conducted to a receptacle.

As previously pointed out the construction of the grate bars and their association one with another is such that ashes and fuel cannot pass through the grate into the compartments 19 in the lower part of the unit. It will be understood also that in the as sembled structure the largest one of the apertures 9 will be so arranged as to discharge air into each compartment as the same moves to position beneath the fuel outlet opening 44 of the pipe 36 so that the greatest amount of air will be passed through the Afresh fuel as it is placed on the grate. As the apertures decrease in size from this point it will, of course, be obvious that the amount of air received by the compartments as they pass this point will be gradually decreased until the smallest aperture is passed after which each compartment will pass over an unperforated section of the air tube 7 where, of course, no air will be received. At this period in the rotation of the grate the Yscraper removes the ashes therefrom. y

Having thus described our invention, what we claim is 1. A grate structure, comprising annular, concentrically arranged bars, means for rotating the bars about an axis concentric therewith, means for discharging fuel onto the bars over a Zone extending radially of the bars for combustion, while the bars are rotating, and means for discharging air upwardly through the grate through predeter mined areas and supplying such areas in successively smaller quantities from the Zone of fuel supply in the direction of rotation of the grate.

2. A rotating grate, comprising a circu lar chamber having bottom and side walls, means for supporting the chamber for rotation in a horizontal plane, a plurality of concentric annular grate bars constituting the top wall of the chamber, said bars having oppositely directed edge flanges arranged in spaced overlapping relation to provide air passages therebetween designed to prevent the downward passage of fuel to the interior of the chamber, means for rotating the chamber and bars, means dividing the chamber into a plurality of radial compartments, means for discharging fuel onto the grate bars in a Zone approximately radially thereof, and means for discharging air into said compartments to give each compartment a maximum amount as it passes beneath the fuel discharging means and Cil thereafter progressively to give each compartment smaller amounts of air.

3. A rotating grate, comprising a circular chamber having bottom and side walls, means forsupporting the chamber for rotation in a horizontal plane, a plurality of concentric annular grate bars constituting the top wall of the chamber, said bars having oppositely directed edge flanges arranged in spaced overlapping relation to provide air passages therebetween designed to prevent the downward passageJ of fuel to the interior of the chamber, means for rotating the chamber and bars, means dividing the chamber into a plurality of radial compartments, means for discharging fuel onto the grate bars over a substantially radial zone, means for discharging air into said compartments whereby each compartment will receive a maximum amount as it passes beneath the fuel discharging means and thereafter progressively receive smaller amounts of air, and means for removing ashes from the grate at a point before the deposit of fuel thereon from the fuel supplying means therefor.

4. A grate structure of the character described, comprising a circular chamber having side and bottom walls, said bottom wall having a central aperture therethrough, means for supporting said chamber horizontally for rotation about a vertical axis, means for discharging air into said chamber through' the aperture in the bottom thereof, a grate constituting the top wall of the chamber and comprising a plurality of concentrically arranged annular bars, means for rotating the chamber, a body disposed centrally of said grate bars and including an upright bearing stud, a fuel conducting pipe disposed above the grate, a bearing ring carried at the inner end of said pipe and engaging over said bearing stud, said pipe having an outlet opening extending longitudinally thereof along the lower side thereof for discharging fuel onto the grate in a zone substantially radially of the grate.

5. A grate structure, comprising a casing mounted for rotation, a grate closing the top of said casing, said casing having a central opening through the bottom thereof, means for rotating said casing and grate, an air pipe extending vertically into said casing through said opening and having a circumferential series of apertures formed through the wall thereof and opening into the casing, said apertures being of gradually decreasing size, partitions in said casing dividing the same into a plurality of radially disposed chambers, each of said partitions having its inner end in close proximity to said air pipe, and means for discharging fuel onto said grate, said fuel discharging means being so disposed above the grate as to discharge the fuel thereonto in a substantially radial zone extending above the larger one of said series of apertures.

6. A flat grate structure, means supporting said grate structure permitting its rotation in a horizontal plane, means for rotating the structure, means for discharging fuel onto the grate structure over a zone extending radially of the pivotal axis thereof, and means for discharging air upwardly through the grate through predetermined areas and supplying such areas with successively smaller quantities of air from the zone of fuel supply in the direction of rotation of the grate.

In testimony whereof we hereunto aflix our signatures.

OSCAR T. SOLBERG. CHRISTIAN M. SHOTT. HARRISON M. IVALKER. 

